Focusing means for incandescent



J. C. ROSE FOGUSING MEANS FOR INCANDESCENT STUDIO SPOTLIGHTS OriginalFiled May 21, 1935 3 SheetIs-Sheet l J C. ROSE May 16, 1939.

FOCUSING MEANS FOR INCANDESCENT STUDIO SPOTLIGHTS Original- Filed May21, 3' Sheets-Sheet 2 Inveniar 55 6. Ease.

J c. ROSE May 16, 1939.

FOCUSING MEANS FOR INQANDESCENT STUDIO SPOTLIGHTS Original Filed May 21,1955 5 Sheets-Sheet 3 Inventor- Jss CiJQose.

Reissued May 16, 1939 UNITED STATES PATENT OFFICE FOC'USIN G MEANS FORINCANDESCENT STUDIO SPOT'LIGHTS Jess 0. Rose, Los Angeles, Calif.,assignor to M- tion Picture Electric Products, Los Angeles,

Calif., a corporation of California 15 Claims.

This invention relates generally to incandescent spot lamps such as areused in motion picture studios for illumination of sets, and moreparticularly to focusing means for the incandescent light globe of suchlamps.

Studio spot lamps of the character mentioned are ordinarily providedwith a light globe that is movable forwardly and rearwardly along theaxis of the reflector, for the purpose of adjusting the lamp to cast arelatively small spot of light, or else to spread the light out andflood the object. The spot is of course formed when the globe is at ornear the focal point of the reflector, and flood characteristics areobtained when the globe is moved nearer the reflector. It has been thepractice to provide an operating means for adjusting the position of theglobe between spot and flood positions involving a lead screw havingscrewthreaded connection with globe carrier member. Such lead screw isordinarily rotated by a crank or similar means, and a large number ofcrank rotations are required to move the globe between spot and floodpositions. Obviously adjustment of such a lamp involves considerableeffort and consumption of time. The time factor involved in adjustingsuch lamps is of particular importance in the lighting of a motionpicture set, since time is at a high premium, and when the taking of ascene is waiting, a motion picture director is highly impatient with theslightest delay in making final lamp adjustments.

It is accordingly one object of the present invention to provide aquickly operating and generally improved means for adjusting the globeof an incandescent studio spotlight between spot and flood positions.

In accordance with a preferred form of the present invention, the lightglobe carriage is arranged to slide on. a pair of guide rods which areparallel to the axis of the reflector, and the carriage is moved througha link connected at one end to the carriage and at the other end to anarm mounted on a manually rotatable shaft journalled in a wall of thelamp. .The arrangement is made such that the full range of movement ofthe lamp globe carriage (between spot and flood positions) isaccomplished by one revolution or less of the manual operating shaft,that is, within one revolution of said shaft, full adjustment being hadin present preferred forms of the invention by a 180 degree turn of saidshaft. A suitable knob or handle is mounted on the manually operable endof the shaft, and the shaft 55 carries a suitable pointer, with which isassociated a scale showing spot, flood, and intermediate positions.

Since in such an arrangement as thus generally described, the lightglobe carriage moves rather freely on its guide rods, the manualadjustment means as described ofnr n; particular resistance, the lightglobe carriage has a tendency to slide along the guide rods as the spotlamp is tilted up or down on its horizontal trunnion mounting axis. Itis a feature of the present invention that such accidental movement ordisplacement of the light globe carriage in the course of ordinaryoperation is prevented. This is accomplished in a preferred embodiment,by the provision of friction means which yieldingly resists adjustmentmovement of the light globe carriage on the guide rods. This frictionmeans offers the necessary resistance to prevent accidental displacementof the carriage, but does not bind the operating means sufficiently tointerfere with desirable ease of operation.

It is customary to transport lamps of the char- I acter mentioned piledone on top of another, with the front faces of the lamps turneddownwardly. The front lenses of the lamps are for this purpose removed,and the crowned back of each lamp projects somewhat within the frontopening of the lamp next above it. The lamp being in such a position,the light globe carriage tends to work downwardly on its guide rods asthe lamps are transported, even despite the frictional means provided toprevent movement in ordinary operation. As the light globe carriage thusworks downwardly, either the spill-ring carried by the carriageimmediately in front of the globe, or the globe itself, is apt finallyto engage the crowned back of the lamp next below. If a spillring is onthe carriage, it is thereupon caused to be bent back, with the frequentresult of coming against and breaking the globe, while if no spill-ringis in place, the globe may becomebroken by direct engagement with thecrowned back of the lamp below.

It is accordingly a further object of the invention to provide a lampthat has a comparatively freely moving light globe carriage, with a.locking arrangement preventing the light globe carriage fromaccidentally moving forwardly from a fixed retracted position when thelamp is in a face-down position.

The invention will now be best understood by referring to the followingdetailed description of typical and preferred embodiments thereof,reference for this purpose being had to the accompanying drawings, inwhich:

Fig. 1 is a front elevation of a lamp embodying my invention, the frontlens being removed and parts being shown in section;

Fig. 2 is a vertical section taken on line 2--2 of Fig. 1, with certainparts shown in elevation;

Fig. 2a is a detail section taken on line 2a-2a of Fig. 2;

Fig. 3 is a View similar to a portion of Fig. 1, but showing the lampcarriage in a different position; v

Fig. 3a is a section as indicated by line 3a3a of Fig. 3;

Fig. 3b is a detail section taken as indicated by line 3b-3b of Fig. 3a;

Fig. 4 is a detail section taken as indicated by line 44 of Fig. 3;

Fig. 5 is a detail taken as indicated by arrows 5-5 in Fig. 1;

Fig. 6 is a view similar to Fig. 4 but modification;

Fig. 7 is a view similar to a portion of Fig. 3 but showing amodification of the lamp carriage operating means; and

Fig. 8 is a view of the back of the lamp, with the crowned back closuremember broken away.

The lamp, designated generally by numeral I9, is made up of front andrear ring frame members I and i2, respectively, formed with inwardlyextending flanges l3 and i4 (see Figs. 1 and 2). Mounted within flangesl3 and H are two substantially semi-cylindric shell or side wall membersIS. The lower edges of these side wall members define an opening whichcommunicates with the interior of a rectangular case or box 8 (Figs. 1and 3c). Ring flange members I3 and I4 terminate at edges ll, asindicated in Fig. 3a. Box I8, is provided with brackets lBa which engagethe undersides of the lower ends of flanges l3 and I4, and screws l9passing downwardly through side walls i5 and flanges 3 and I4 threadedinto brackets |8a hold the parts in assembly, all as illustrated inFigs. 3a and 3b. This casing member I8 is designed to house certainoperating mechanisms for the carriage, etc., and may for the purpose ofcertain of the claims be considered as a part of the lamp frame.

Rearward ring frame |2 has an opening 22 adapted to receive a rearannular closure member 23 carrying a usual curved reflector 'mirror 24.The back of the reflector is yieldingly supported by an arrangement offour coil springs 24a covered with a suitable padding material, asasbestos, as indicated at 242), thejunctures of the several springsbeing connected by means of supporting wires are to annular member 23.The lamp has a crowned back member 230,, which is showing a secured tomember 23, as shown.

Front frame ring ll has an annular opening 25 which receives a carriagering 26 in which is mounted front glass or lens member 21. The lamp istrunnioned on a horizontal axis at 28 and 29 on the upper ends ofsupporting arms 32 mounted on a usual standard 33.

The incandescent lamp globe is designated at 30, and is shown mounted ona lamp globe carriage 3| which is adapted to slide forwardly andrearwardly, in a direction parallel tothe axis of mirror 24, on a pairof parallel guide rods 34 and 35 which are mounted at their ends inbrackets 36 formed on the inner surfaces of the ends of box l8. Asclearly shown, these-rods are parallel to the axis of mirror 24 and arein a horizontal plane. Carriage 3| is provided with a hearing 31 whichslides freely on guide rod 35,

and with forward and rearward bearings 38 and 39 which slide freely onguide rod 34.

Carriage 3| is shown provided with a forwardly extending bracket 49 onwhich is mounted the supporting arm 4| of a conventional spill-ring 42,which is positioned immediately in front of light globe 30. As a meansfor detachably mounting arm 4| on bracket 4!), arm 4| is provided withan open-ended slot 43 which is adapted to receive a clamp screw 44mounted in bracket 40, a wing nut 45 being provided on screw 44 to bearagainst the side of arm 4| and thus clamp it tightly to bracket 49. Itwill be evident that this construction permits the spill-ring to beeasily and quickly mounted and dismounted.

The preferred means in accordance withvthe present invention for slidinglamp carriage 3| back and forth on rods 34 and 35, for the purpose ofadjusting the lamp globe between flood and spot positions, will now bedescribed. A horizontal operating shaft 59 is rotatably mounted in sidewall 5| of box I8 (Figs. 2 and 4) This shaft is so located as to be tothe rear of forward lamp-carriage bearing 38 when the lampcarriage is inits rearward or flood position, as it is in Fig. 2, and is located justbelow guide rods 34 and 35, as shown. Pinned on the inner end of shaft50 is an arm 52, the swinging end of which is pivotally connected to oneend of a link 53, the other end of link 53 being pivotally connected at54 with lamp-carriage bearing 38.

The outer end of shaft 5|] is provided with an operating knob 51provided with a handle 58 and a pointer 59, the latter moving over scale60 formed on a scale plate 6| which is affixed, as by screws 62, to theouter surface of wall 5|.

It will be evident from a consideration of Figs. 2 and 3 that the fullrange of forward and rearward movement of the lamp carriage isaccomplished by a 180 degree rotation of shaft 59 and arm 52. The lampcarriage is in its rearmost (flood-light) position when arm 52 is in ahorizontal rearwardly extended position, and is in its extreme forwardposition (spot) when arm 52 is in a horizontal forwardly extendingposition, globe 39 being substantially at the focal point of mirror 24in the latter position. The range of movement of the lamp carriage is ofcourse determined by the length of arm 52, and link 53 is of such lengthas will place the carriage and lamp in correct full-flood and spotpositions in the two described positions of arm. 52. Pointer 59 is somounted on shaft as to point straight rearwardly when the lamp carriageis in its rearmost or flood position, and to point straight forwardlywhen the carriage is in its extreme forward or spot position. These twopositions are designated on scale 65 as flood and spot, respectively.The 180 range of movement of pointer 59 is then divided into ten scaledivisions designated by numerals l, 2, 3, etc. In Fig. 3 the carriage isillustrated in a position close to spot, and in Fig. 5 the pointer isshown in a corresponding position.

In the position of Fig. 2, arm 52 is just above horizontal position andis in engagement with guide rod 34, which overlies arm 52 and provides astop therefor (see Fig. 2a). When arm 52 is thus in engagement withguide rod 34, pointer 52 is It Will be a pin 8| set into said shaft.

advantage of this look position will be explained hereinafter.

A friction means is provided to establish a desirable resistance tomovement of the lamp carriage on the guide rods, so that the carriagewill move easily when handie 58 is turned, but will not slide back andforth as the lamp is: tilted up or down. As shown in Fig. 4, operatingshaft 50 is provided just inside of wall with a friction disk 13, saiddisk in the present instance being provided with a hub 1| fastened toshaft 50 by means of pin i2. Disk 19 comes against one side of astationary friction disk 14 carried by the outer ends of theaforementioned screws 62,. disk ll being positioned between sleeves 15bearing against wall 5| and nuts 16 being: screwthreaded on the rearends of the screws. Mounted on shaft soas to bear against the surface ofdisk 14 which is: opposite disk in, is a friction. disk 18, said. disk.18 being provided with. a hub 19 which is arranged. to slidelongitudinally on shaft 50 but is held against rotation. thereon- Forinstance, hub 19 may be formed with a slot formed in a directionparallel to shaft 50,. which slot receives Friction disk 18 is thussplined on. shaft 50 Encircling shaft 50 and bearing against the end. ofhub 19 is a. compression. spring 83, the other end of which seatsagainst a collar 84 tightly mounted on shaft 50, all as clearly shown inFig. 4. It will be evident that spring 83 presses friction disk 18 intotightengagement with one surface of stationary frie tion disk M, andalso acts through collar 84 and shaft 59- to press disk In into tightengagement with the other surface of disk 14,. thus setting up yieldableor frictional resistance to rotation of shaft 50. The adjustment ofspring 83 is of course such, however, that shaft 50 may be turnedwithout difliculty, only sufiicient frictional resistance being. set upto prevent carriage 3| from sliding back and forth on the guide rodsmerely due to tilting of the lamp.

It will now be evident that I have provided a novel lamp carriageadjustment mechanism which is quick in action, simple in construction,and

convenient in use. The operating handle, in the preferred form of thelamp, is rotated through but one half of a turn to translate the lampcarriage over its entire range of movement. The mechanism moves easily,but is prevented from accidental displacement from a given position asthe lamp is tilted, by the yielding friction means acting on the manualoperating shaft.

When lamps of the type disclosed are to be transported, they arecommonly stacked one on top of another, with their crowned backs up, andthe front lens carrying rings removed, so that the crowned back of eachlamp may be received within the open side of the lamp above it. When thelamps are so stacked, the operating handle is turned to lock position,which places the lamp carriage in the position of Fig. 2. In suchposition, as mentioned previously, arm 52 is past center and inengagement with guide rod 34, and

4 the lamp carriage is stopped against sliding downwardly on rods 34 and35, with the liability of finally breaking the light globe.

Attention is called to the fact that the lamp carriage, guide rods, andfocusing mechanism are supported exclusively on lower housing H3, andthat this entire assembly may be removed simply by removing screws Nthat secure housing l8 to frame ring flanges I3 and I4.

Fig. 6 shows a modification of the lamp carriag'e operating means. Theoperating link which is connected to the lamp carriage is againindicated at 53, and the casing wall and scale plate are again indicatedby numerals 5| and 8|, respectively. Itwill be understood that the lampcarriage and link 53 may be exactly the same as in the form previouslydescribed, as may the mechanism casing of which wall 5| is a part. Amanual operating shaft is journalled in wall 5| on an axis which islocated the same as is the axis of shaft 50 in the form of Fig. 4. Theexterior end of shaft 90 carries a handle 9| and a pointer 92, and itsinner end is reduced, as at 93, and is slidably received within a socket94 formed in the end of a shaft member 95. Reduced shaft end 93 has anotch 96 adapted to receive and drivingly engage a cross-pin 91 set insocket 9t. Shaft member 95, which is journalled in a bearing' 98 carriedby a stationary frame plate 99, is confined against longitudinalmovement by means of a flange |B|l near itsinner end which engages theadjacent surface of bearing 98, and a collar |fl| screwthreaded onto theshaft and positioned adjacent the opposite face of said bearmg.

On the extreme inner end of shaft 95 is pinned an arm 52', exactlysimilar to the arm 52 of the previously described form shown in Fig. l,the outer end of arm 52' being pivotally connected to the end of link53, as in the previous instance. It will be evident that rotation ofknob 9| and shaft 90 will cause shaft 95 to be rotated to swing arm 52for the purpose of moving link 53 and so shifting the lamp carriage,substantially as in the previous form.

A locking device is provided to prevent accidental shifting of thefocusing mechanism as the lamp is tilted. Pinned on shaft 90 adjacentthe inner surface of wall 5| is a spur gear M6, and, normally meshingtherewith is a stop element HIT, which is set into wall 5|, as clearlyshown in Fig. 6. It will be evident that with the parts in the positionof Fig. 6, the stop element in engagement with the teeth of gear HIEprevents shaft 90 from being rotated. But by grasping knob 9| andforcing shaft 90 inwardly until gear W5 is free of element I01, themechanism may be freely operated. Shaft 96' is normally' yieldinglyheldin the locked position of Fig. 6 by means of a coil compression springHi8 which is confined between flange It!!! and the opposed face of spurgear H16. Thus, to change the focus of the lamp, knob 9| is grasped andforced inwardly against spring I08 to free gear [06 from element I91,and may then be rotated to accomplish the desired shift of the lamp car-I riage. When knob 9| is then released, spring IE8 acts to move shaft 90back to the position of Fig. 6', gear Hi5- moving back into lockingengagement with locking element I01. The lamp carriage is thereforeautomatically locked against movement longitudinally on the guide rodsat all times that knob 9| is not being manually pressed inwardly tooperating position, and the lamp carriag'e is therefore prevented duringnormal use of the lamp from sliding back and forth on its guide rods asthe lamp is tilted.

Fig. 7 shows another variational form of the lamp carriage operatingmeans. In this instance the lamp carriage is shown provided on its"underside with a rack H2, and adapted to mesh with this rack is a. gearsegment H3 fast on an operating shaft I" which will be understood asjournalled for rotation in the side wall of the enclosing case. Rotationof shaft H4, which will be understood. as accomplished by a manual knobof the same type as illustrated in Fig. 4, causes rotation of gear H3 totranslate rack I !2 and the lamp carriage between its proper limits ofoperation. The diameter of gear H3 is preferably such as will causetranslation of the lamp carriage between such limits by a half-rotationof shaft I i l.

Shaft He is preferably provided with a friction retarding means the sameas is illustrated in Fig. 4, it being understood that Fig. 4 isillustrative of the friction means and operating knob used with shaft H4of Fig. '7. It will be noted, however, that shaft H4 must be rotated ina direction opposite to that of shaft 50 of Fig. 4 in order toaccomplish a given adjustment of the lamp carriage.

Fig. 7 also shows locking means adapted to hold the lam-p carriagesecurely in a retracted position during transportation of the lamp. Forthis purpose, gear member H3 is provided with a rounded portion i2lladapted to come into engagement with an arcuate surface lZi at the outerend of rack member H2 after gear H3 has been moved out of mesh with therank at the inner limit of lamp carriage movement. It will be obviousthat when surface l2il is in engagement with surface Hi, the lampcarriage is securely locked against translation on the guide rods.

It will be understood the drawings and description are to be consideredmerely as illustrative of and not restrictive on the broader claimsappended hereto, for various changes in design, structure andarrangement may be made Without departing from the spirit and scope ofsaid claims.

I claim:

1. In a studio spot lamp embodying a lamp casing having an optical lightprojecting and focusing element therein, the combination of a lightsource carriage Within said casing adapted to car ry a light source onthe axis of said optical ele ment, means supporting and guiding saidcarriage for forward and rearward movement in a direction parallel tothe optical axis of said optical element, whereby said light source ismovable between spot and flood positions, a manually rotatable shaftextending through a wall of said casing on an axis at right angles tothe direction of carriage movement, an operative interconnection betweenth portion of said shaft that is inside the casing and said carriage soarranged that the light source is moved between spot and full floodpositions within one revolution of the manually rotatable shaft, andmanual shaft rotating means operating on the exterior portion of theshaft.

2. A studio spot lamp embodying a substantially cylindric lamp casing,an optical light projecting and focusing element therein, a dependingmechanism enclosing casing joined to said cylindric lamp casing at thebottom thereof, said two casings opening into one another, a lightsource carriage within said cylindric lamp casing adapted to carry alight source on the axis of said optical element, means supporting andguiding said carriage for forward and rearward movement in a. directionparallel to the optical axis of said optical element, whereby said lightsource is movable between spot and flood positions, a horizontalmanually rotatable shaft extending through a side wall of said dependingmechanism enclosing casing and disposed at right angles to the directionof carriage movement, an operative interconnection between the portionof said shaft that'is inside the casing and said carriage so arrangedthat the light source is moved between spot and full flood positionswithin one revolution of the manually rotatable shaft, and manual shaftrotating means operating on the exterior portion of the shaft.

3. In a studio spot lamp embodying a lamp casing having an optical lightprojecting and focusing element therein, the combination of a lightsource carriage within said casing adapted to carry a light source onthe axis of said optical element, means supporting and guiding saidcarriage for forward and rearward movement in a direction parallel tothe optical axis of said optical element, whereby said light source ismovable between spot and flood positions, a manually rotatable shaftextending through a wall of said casing on an axis at right angles tothe direction of carriage movement, an operative interconnection betweenthe inner portion of said shaft and the carriage so arranged that thelight source is moved between spot and full flood positions within onerevolution of the manually rotatable shaft, and friction meansyieldingly resisting operation of the manual shaft.

4. A studio spot lamp embodying a substantially cylindric side wallcasing, an optical light projecting and focusing element therein, adepending mechanism enclosing casing joined to said side wall casing atthe bottom thereof, said two casings opening into one another, a lightsource carriage within said cylindric casing adapted to carry a lightsource on the axis of said optical element, means supporting and guidingsaid carriage for forward and rearward movement in a direction parallelto the optical axis of said optical element, whereby said light sourceis movable between spot and flood positions, a horizontal manuallyrotatable shaft extending through a side wall of said dependingmechanism enclosing casing and disposed at right angles to the directionof carriage movement, an operative interconnection between the innerportion of said shaft and the carriage so arranged that the light sourceis moved between spot and full flood positions within one revolution ofthe; manually rotatable shaft, and friction means yieldingly resistingoperation of the manual shaft.

5. In a studio spot lamp embodying a lamp casing having an optical lightprojecting and focusing element therein, the combination of a lightsource carriage within said casing adapted to carry a light source onthe axis of said optical element, means supporting and guiding saidcarriage for forward and rearward movement in a direction parallel tothe optical axis of said optical element, whereby said light source ismovable between spot and flood positions, a manually rotatable shaftextending through a wall of said casing on an axis at right angles tothe direction of carriage movement, an operative interconnection betweenthe inner portion of the shaft and the light source carriage, such thatrotation of the shaft through agiven angle moves the carriage betweenspot and flood positions. a friction disk nonrotatably mounted on saidmanual shaft, and a stationary friction member frictionally engaged bysaid friction disk.

6. In a studio spot lamp embodying a lamp casing having an optical lightprojecting and focusing element therein, the combination of a lightsource carriage within said 'casing adapted to carry a light source onthe axis of said optical element, means supporting and guiding saidcarriage for forward and rearward movement in a direction parallel tothe optical axis of said optical element, whereby said light source ismovable between spot and flood positions, a manually rotatable shaftextending through a wall of said casing on an axis at right angles tothe direction of carriage movement, an operative interconnection betweenthe inner portion of the shaft and the light source carriage, such thatrotation of the shaft through a given angle moves the carriage betweenspot'and flood positions, a friction disk splined on said manual shaft,a coil spring member surrounding said shaft and arranged to press saidfriction disk in one direction on the shaft, and a stationary frictionmember frictionally engaged by said spring urged friction disk.

7. In a studio spot lamp embodying a. lamp casing having an opticallight projecting and focusing element therein, the combination of alight source carriage within said casing adapted to carry a light sourceon the axis of said optical element, means supporting and guiding saidcarriage for forward and rearward movement in a direction parallel tothe optical axis of said optical element, whereby said light source ismovable between spot and flood positions, a manually rotatable shaftextending through a wall of said casing on an axis at right angles tothe direction of carriage movement, an arm on the inner portion of saidmanual shaft, and a link connected between the swinging end of said armand said carriage.

8. In a studio spot lamp embodying a lamp cas-' ing having an opticallight projecting and focusing element therein, the combination of alight source carriage within said casing adapted to carry a light sourceon the axis of said optical element, means supporting and guiding saidcarriage for forward and rearward movement in a direction parallel tothe optical axis of said optical element, whereby said light source ismovable between spot and flood positions, a manually rotatable shaftextending through a wall of said casing on an axis at right angles tothe direction of carriage movement, an arm on the inner portion of saidmanual shaft, a link connected between the swinging end of said arm andsaid carriage, a friction disk splined on said manual shaft, a coilspring member surrounding said shaft and arranged to press said frictiondisk in one direction on the shaft, and a stationary friction memberfrictionally engaged by said spring urged friction disk.

9. In a studio spot lamp embodying a lamp casing having an optical lightprojecting and focusing element therein, the combination of a lightsource carriage within said casing, a pair of parallel horizontal guiderods extending parallel to the axis of said optical element in the lowerpart of the lamp casing, said guide rods supporting said light sourcecarriage for sliding movement therealong, such that a light sourcecarried by the carriage moves along the axis of said optical element, ahorizontal manually rotatable shaft extending through a wall of thecasing just below and at right angles to said parallel guide rods, anoperative connection between the inner portion of said shaft and thecarriage so arranged that the light source is moved between spot andfull flood positions within one revolution of the manually rotatableshaft, and manual shaft rotating means operating on the exterior portionof the shaft.

10. In a studio spot lamp embodying a lamp casing having a curvedreflector disposed within the rearward portion thereof, the combinationof a light source carriage within said casing, a pair of parallelhorizontal guide rods extending parallel to the axis of the reflector inthe lower part of the lamp casing, said guide rods supporting saidlightsource carriage for sliding movement therealong, such that alightsource carried by the carriage moves along. the of the reflector, ahorizontal manually rotatable shaft extending through the casing justbelow and at right angles to said parallel guide rods, an arm on theinner portion of said manual shaft, a link pivotally connected at oneend to the swinging end of said arm, and extending from said pivotalconnection in a forward direction in the lamp to a forwardpivotalconnection with. the light source carriage, and manual shaft rotatingmeans operating the exterior portion of the shaft.

11. A studio spot lamp embodying a substantially cylindric side wallcasing, optical light projecting and focusing element therein, adepending mechanism enclosing casing joined to said side wall casing atthe bottom thereof, said two casings opening into one another, a lightsource carriage within said cylindric casing adapted to carry a lightsource on the axis of said optical element, means supporting and guidingsaid carriage for forward and rearward movement in a direction parallelto-the optical axis of said optical element, whereby said light sourceis movable b-etween spot and flood positions, a horizontal manuallyrotatable shaft extending through a side wall of said dependingmechanism enclosing casing and disposed at right angles to the directionof carriage movement, said shaft extending exteriorly of said casing andhaving an operating handle on its outer end, and an operativeinterconnection between the inner end of said shaft and the carriage soarranged that the light source is moved between spot and full floodpositions within one revolution of the manually rotatable shaft.

12. In a studio spot lamp embodying a lamp casing having a curvedreflector disposed within the rearward portion thereof, the combinationof a light source carriage within said casing, a pair of parallelhorizontal guide rods extending parallel to the axis of the reflector inthe lower part of the lamp casing, said guide rods supporting said lightsource carriage for said sliding movement th-erealong, such that a lightsource car'- ried by the carriage moves along the axis of the reflector,ahorizontal manually rotatable shaft extending through a wall of thecasing just below and at right angles to said parallel guide rods, anoperating arm on the inner portion of said manual shaft, and a link,pivotally connected at one end of the swinging end of said arm andextending from said pivotal connection in a forward direction in thelamp to a forward pivotal connection with the light source carriage,said arm and link being so arranged as to move the carriage from itsextreme rearward to its extreme forward position by a movement of thearm from a rearwardly extended position downwardly and around to aforwardly extended position, theswinging end of said operating arm beinglocated directly below one of said guide rods, and being engageabletherewith when said arm is raised from said rearwardly extended position,to a position above horizontal to afford a stop to forward movement ofthe carriage.

13. In a studio spot lamp embodying a lamp casing having an opticallight projecting and focusing element therein, the combination of alight source carriage within said casing adapted to carry a light sourceon the axis of said optical element, means supporting and guiding saidcarriage for forward movement in a direction parallel to the opticalaxis of said optical element, whereby said light source is movablebetween spot and flood positions, a horizontal manually rotatable shaftjournalled in said casing on an axis at right angles to the direction ofcarriage movement, a rotatable shaft journalled in line with saidmanually rotatable shaft, an operative connection between the lastmentioned shaft and the lamp carriage, a sliding driving connectionbetween said shafts such that the manual shaft may be moved axiallywithout breaking its driving connection with the other shaft, a lockingmember on said manual shaft, a stationary locking element engageablewith said locking member to lock the manual shaft against rotation inone axial position of said shaft, and a spring yieldingly urging saidmanual shaft to such locking position, but yieldable to allow the manualshaft to be moved axially to disengage said locking member from saidlocking element.

14. In a studio spot lamp embodying a lamp casing having an opticallight projecting and focusing element therein, the combination of alight source carriage within said casing adapted to carry a light sourceon the axis of said optical element, means supporting and guiding saidcarriage for forward and rearward movement in a direction parallel tothe optical axis of said optical element, whereby said light source ismovable between spot and flood positions, a rack on the lamp carriageextending parallel to the direction of carriage movement, a manuallyrotatable shaft extending through a wall of said casing on an axis atright angles to the direction of carriage movement, manual shaftrotating means operating on the exterior portion of the shaft, and aspur gear on said shaft meshing with said rack, said spur gear being ofsuch size that the light source is moved between spot and full floodpositions within one revolution of said rotatable shaft.

15. A studio spot lamp embodying a substantially cylindric lamp casing,an optical light projecting and focusing element therein, a dependingmechanism enclosing casing detachably mounted on the lower side of saidlamp casing, said two casings opening into one another, a light sourcecarriage within said cylindric lamp casing adapted to carry a lightsource on the axis of said optical element, means mounted on saiddetachable casing supporting and guiding said car- :1

riage for forward and rearward movement in a direction parallel to theoptical axis of said optical element, whereby said light source ismovable between spot and flood positions, a horizontal manuallyrotatable shaft extending through a side wall of said dependingmechanism enclosing casing and disposed at right angles to the directionof carriage movement, an operative interconnection between the innerportion of said shaft and said carriage s0 arranged that the lightsource is moved between spot and full flood positions within onerevolution of the manually rotatable shaft, and manual shaft rotatingmeans operating on the exterior portion of the shaft.

JESS C. ROSE.

